It was the night before Christmas, and Ebenezer Scrooge was facing the three ghosts. Or was he?

Robert Chance Algar, a Californian neurologist, and his aunt Lisa Saunders, a medical writer and physician, believe that the affliction that made Scrooge a byword for miserliness and redemption was Lewy body dementia (LBD), a disease so complex that doctors did not include it in the medical lexicon until 1996.